Skeletal muscle is a highly adaptable tissue which can alter not only its mass but also its metabolic profile. It is important to comprehend that as a tissue it is composed not only of the contractile cells, the myofibres, but also vascular, neural and connective tissue components. Therefore whenever an adaptive process brings about a change in the myofibres, it is essential that the other components also undergo remodeling to form a functionally efficient tissue.

‘Muscle doubling’ is a feature found in many vertebrates in which animals develop up to three times the normal muscle mass. However it has been argued that this muscle is not functional as it contains only non-fatigue resistant fibres. Here we determined the impact of introducing a programme of oxidative metabolism on a background of hypertrophic muscle.

The results of this study challenge some of the established concepts in skeletal muscle biology. We also discuss how the finding of this study could be used in a clinical setting to address issues such as aged related muscle loss.